A cardiac pump

Abstract

A cardiac pump includes a housing, a rotor extending along a rotational axis of the cardiac pump between first and second axial ends of the rotor, and a bearing assembly which supports the rotor within the cardiac pump housing for rotation about the rotational axis. The rotor includes a recess formed in an axial end face of the rotor. The housing includes a protruding portion extending axially into the recess. The bearing assembly includes: a first magnet assembly provided on a portion of the housing radially outward of the recess formed in the rotor, a second magnet assembly provided on a portion of the rotor radially outward of the protruding portion of the housing, and a third magnet assembly provided on the protruding portion of the housing. The first, second and third magnet assemblies at least partially overlap one another in a direction parallel with the rotational axis.

1 . A cardiac pump comprising:
 a housing;   a rotor extending along a rotational axis of the cardiac pump between first and second axial ends of the rotor; and   a bearing assembly, wherein the bearing assembly is configured to support the rotor within the cardiac pump housing for rotation about the rotational axis, wherein the rotor comprises a recess formed in an axial end face of the rotor, wherein the housing comprises a protruding portion extending axially into the recess, and wherein the bearing assembly comprises:
 a first magnet assembly provided on a portion of the housing radially outward of the recess formed in the rotor; 
 a second magnet assembly provided on a portion of the rotor radially outward of the protruding portion of the housing; and 
 a third magnet assembly provided on the protruding portion of the housing, wherein the first, second and third magnet assemblies at least partially overlap one another in a direction parallel with the rotational axis. 
   
     
     
         2 . The cardiac pump of  claim 1 , wherein the first axial end of the rotor is an outlet end and the second axial end of the rotor is an inlet end, wherein the recess is formed in the axial end face at the outlet end of the rotor. 
     
     
         3 . The cardiac pump of  claim 1 , wherein the first magnet assembly comprises a plurality of magnets arranged to produce a stronger magnetic field adjacent the first magnet assembly in a radially inward direction and a weaker magnetic field adjacent to the first magnet assembly in a radially outward direction. 
     
     
         4 . The cardiac pump of  claim 1 , wherein the first magnet assembly comprises a half or full Halbach array of magnets arranged to produce a stronger magnetic field adjacent the first magnet assembly in a radially inward direction and a weaker magnetic field adjacent to the first magnet assembly in a radially outward direction. 
     
     
         5 . The cardiac pump of  claim 1 , wherein the first magnet assembly comprises:
 a first housing magnet, arranged such that a magnetic dipole moment of the first housing magnet is aligned with a first direction parallel with the rotational axis; and   a second housing magnet, arranged such that a magnetic dipole moment of the second magnet is aligned with a second direction opposite the first direction.   
     
     
         6 . The cardiac pump of  claim 5 , wherein the first magnet assembly comprises a pole piece arranged between the first and second housing magnets. 
     
     
         7 . (canceled) 
     
     
         8 . The cardiac pump of  claim 1 , wherein the second magnet assembly comprises.
 a first rotor magnet, arranged such that a magnetic dipole moment of the first magnet is aligned with a first direction parallel with the rotational axis; and   a second rotor magnet adjacent the first rotor magnet, arranged such that a magnetic dipole moment of the second magnet is aligned with a second direction opposite the first direction.   
     
     
         9 . The cardiac pump of  claim 1 , wherein the second magnet assembly comprises:
 a first rotor magnet, arranged such that a magnetic dipole moment of the first rotor magnet is aligned with a first direction parallel with the rotational axis;   a second rotor magnet, arranged such that a magnetic dipole moment of the second rotor magnet is aligned with a second direction opposite the first direction; and   a pole piece arranged between the first and second rotor magnets.   
     
     
         10 . The cardiac pump of  claim 1 , wherein the third magnet assembly comprises a plurality of magnets arranged to produce a stronger magnetic field adjacent the third magnet assembly in a radially outward direction and a weaker magnetic field adjacent to the third magnet assembly in a radially inward direction. 
     
     
         11 . The cardiac pump of  claim 1 , wherein the third magnet assembly comprises a half or full Halbach array of magnets arranged to produce a stronger magnetic field adjacent the third magnet assembly in a radially outward direction and a weaker magnetic field adjacent to the third magnet assembly in a radially inward direction. 
     
     
         12 . The cardiac pump of  claim 1 , wherein the third magnet assembly comprises;
 a fourth housing magnet, arranged such that a magnetic dipole moment of the fourth housing magnet is aligned with a first direction parallel with the rotational axis; and   a fifth housing magnet, arranged such that a magnetic dipole moment of the fifth housing magnet is aligned with a second direction opposite the first direction.   
     
     
         13 . (canceled) 
     
     
         14 . The cardiac pump of  claim 1 , wherein the bearing assembly further comprises a fourth magnet assembly provided on the housing and a fifth magnet assembly provided on the rotor, wherein the fourth and fifth magnet assemblies are spaced apart from the recess in the rotor in a direction parallel with the rotational axis, and wherein the fourth and fifth magnet assemblies at least partially overlap one another in a direction parallel with the rotational axis. 
     
     
         15 . (canceled) 
     
     
         16 . The cardiac pump of  claims 14 , wherein the cardiac pump further comprises a magnetic drive assembly comprising one or more drive magnets for driving rotation of the rotor relative the housing, wherein the one or more drive magnets are arranged between the first, second and third magnet assemblies, and the fourth and fifth magnet assemblies. 
     
     
         17 . The cardiac pump of  claim 14 , wherein the fifth magnet assembly comprises:
 a third rotor magnet, arranged such that a magnetic dipole moment of the third magnet is aligned with a first direction parallel with the rotational axis; and   a fourth rotor magnet adjacent the third rotor magnet, arranged such that a magnetic dipole moment of the fourth rotor magnet is aligned with a second direction opposite the first direction.   
     
     
         18 . The cardiac pump of  claim 14 , wherein the fifth magnet assembly comprises:
 a third rotor magnet, arranged such that a magnetic dipole moment of the third magnet is aligned with a first direction parallel with the rotational axis; and   a fourth rotor magnet, arranged such that a magnetic dipole moment of the second magnet is aligned with a second direction opposite the first direction; and a pole piece arranged between the third and fourth rotor magnets.   
     
     
         19 . The cardiac pump of  claim 14 , wherein the fourth magnet assembly comprises a plurality of magnets arranged to produce a stronger magnetic field adjacent the fourth magnet assembly in a radially inward direction and a weaker magnetic field adjacent to the fourth magnet assembly in a radially outward direction. 
     
     
         20 . The cardiac pump of  claim 14 , wherein the fourth magnet assembly comprises a half or full Halbach array of magnets arranged to produce a stronger magnetic field adjacent the fourth magnet assembly in a radially inward direction and a weaker magnetic field adjacent to the fourth magnet assembly in a radially outward direction. 
     
     
         21 . (canceled) 
     
     
         22 . The cardiac pump of  claim 14 , wherein the fifth magnet assembly comprises a plurality of magnets arranged to produce a stronger magnetic field adjacent the fifth magnet assembly in a radially outward direction and a weaker magnetic field adjacent to the fifth magnet assembly in a radially inward direction. 
     
     
         23 . (canceled) 
     
     
         24 . The cardiac pump of  claim 1 , wherein the protruding portion of the housing is configured to engage the rotor at the recess to form a plane bearing between the housing and the rotor at the first end of the rotor. 
     
     
         25 . The cardiac pump of  claim 1 , wherein the housing is configured to engage the rotor at the second end of the rotor to form a further plane bearing between the housing and the rotor at the second end of the rotor.